


Keeping Up Appearances

by Useless19



Series: Getting Over It [2]
Category: Transformers - All Media Types, Transformers: Prime
Genre: Bondage, Break Up, M/M, Size Difference, Size Kink, Sticky Sexual Interfacing, Throne Sex
Language: English
Status: Completed
Published: 2019-07-12
Updated: 2019-07-12
Packaged: 2020-06-26 23:21:33
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 7,833
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19778569
Author URL: https://archiveofourown.org/users/Useless19/pseuds/Useless19
Summary: With any relationship, there are ups and downs. Knock Out probably should've expected things to be rockier than usual when it involved Megatron.Snippets of Knock Out’s relationship with Megatron throughout the rest of the series.





	Keeping Up Appearances

**Author's Note:**

> So this was mostly an excuse to write a bit of smut and get my headcanon for this relationship out. I do intend for there to be a part 3 in this series, but we’ll have to see how things go.

Post _Inside Job_

Well, this was a fantastic situation to be in.

And by _fantastic_ , Knock Out meant _completely intolerable_.

Any reasonable mech would think that clanging the leader of the glorious Decepticon empire would give one a certain amount of leeway. An extra bit of tolerance for when accidents happened.

 _Not_ getting left stuck in a wall for the common foot soldiers to snigger at, that was for sure!

Knock Out ex-vented — as much as he was able to with half his vents unable to expel air into solid metal — and stretched what he could. It wasn't much: helm, servos, and right leg. The majority of his chassis was stuck and no amount of wiggling was getting him any closer to freedom.

There must be some way he could convince Megatron to release him.

Well, putting it like that, there was definitely one thing Knock Out could think of. He shifted his leg again and — yes, his aft was just free enough that someone who was familiar with it would be able to reach his valve.

Megatron would use his digits and —

His hand. The hand of a _Prime_. Knock Out shivered. Megatron had the arm of a Cybertronian blessed by Primus himself and he could make Knock Out overload with it.

Delicious.

And blasphemous to be sure, but who really cared about that these days? Primus was dead and Cybertron along with him. Your average mech didn't hold much stock in religion.

With the wall restricting his transformations, there was no way Knock Out would be able to take all of Megatron like this. He'd have to use a smaller spike setting, but it'd feel just as big with the pressure surrounding him.

He’d press in, taking up every last centimetre of space, until Knock Out was gasping and still demanding more.

In reality, Megatron wouldn’t be able to hear Knock Out, not unless they were both on a short-range frequency and were happy with anyone wandering the nearby corridors of the _Nemesis_ listening in.

But this was in Knock Out’s processor and he could fantasise however he wanted.

Back to the important thoughts, like Megatron's nice, thick —

Someone reset their vocaliser loudly in front of Knock Out. He opened his optics warily, not entirely sure he hadn't said anything out loud.

Dreadwing was stood before him with a sledgehammer in one servo.

“I'm to be set free? Already?” Knock Out asked. It had barely been more than a few hours, all told.

“Your services are required,” Dreadwing said, in an extremely threatening tone.

Granted Dreadwing often sounded like he was contemplating ripping out your spark but it felt a lot more dangerous when you were unable to flee.

“About t— _ah!_ ” Knock Out cut himself off with a yelp as Dreadwing slammed the sledgehammer into the wall above his head. “A little warning, perhaps?”

Dreadwing grinned. It looked like Knock Out had been wrong about a lack of a sense of humour. His frame was promisingly big too. Maybe he'd be worth keeping in mind if Knock Out ever got bored of Megatron.

A few more strut-rattling smashes and he was free.

“Now,” Knock Out said, brushing dust and debris off his pristine coat, “what exactly am I needed for?”

* * *

Post _Patch_

Megatron rolled off of Knock Out with a satisfied sigh. Knock Out took a moment to realign his hip servos before fully relaxing.

That had been nice, but Megatron had been slower than usual to follow orders, often scrutinising Knock Out before he complied — probably due to being stuck in Starscream’s head for a few hours. That would screw with anyone.

Still, it had left Knock Out somewhat frustrated.

Megatron ex-vented loudly and stared at the ceiling.

“Why did you join the Decepticons, Knock Out?”

“Who doesn't want to be on the winning team?” Knock Out said glibly.

Megatron said nothing and Knock Out wondered if he'd put his wheel in it. Time to play nice and figure out what Megatron wanted to hear.

“Quips aside, I think this is the best place for me,” Knock Out continued carefully. “The Autobots would never have allowed me to be a medic — given my lack of official qualifications — or indulged my skills as a torturer. Skills I rather like having and getting to use from time to time.”

Megatron hummed thoughtfully. Knock Out relaxed and —

Megatron was suddenly above Knock Out, heavy clawed servo pressing him into the berth.

“Attempt to assassinate me again and I will rip you apart,” Megatron snarled, claws digging in painfully and scratching ugly marks into his paint. “Are we clear?”

“Perfectly, Lord Megatron,” Knock Out squeaked.

So _not_ because of Starscream then. Or rather, because of what he’d seen of Knock Out while looking over Starscream’s memories.

Thank goodness Dreadwing hadn't mentioned what he'd seen in the medbay.

Megatron slowly drew back, leaving Knock Out to desperately kill off all the warnings raised by his combat protocols. One of his sawblades had transformed out in his panic, he hastily flipped it back into his forearm.

“Do you really want to be second in command, Knock Out?” Megatron asked, ignoring Knock Out’s slow-dissipating fright. “The position comes with more responsibility than power. It would be ill-suited to your abilities and tastes.”

“I can safely say my ambitions have lowered since then,” Knock Out said, “I’m perfectly happy being the ship’s medic. I don’t want to fight Starscream for the post.”

Starscream could get _nasty_ when defending his position and Knock Out didn’t want to deal with another _cosmetic_ punishment if he could avoid it.

Knock Out waited, but it seemed Megatron's grievances were done for the moment. Knock Out shifted his hips, not too much of an ache, good. Maybe he could go for quantity over quality in his overloads tonight.

“Another?” Knock Out asked, claws tracing up Megatron's chest plate.

Megatron's mouth curved up into the first proper smile Knock Out had seen that evening.

“Insatiable.”

“You’ll just have to try _harder_.”

Megatron laughed and pulled Knock Out on top of him. Good. Hopefully, that meant things were forgiven and forgotten.

* * *

Post _Darkmount, NV_

“Soundwave, see to it that we are not disturbed.”

Soundwave obligingly turned his back to Megatron and input a string of commands into his data station. Knock Out couldn’t tell what he was doing from this far away.

“Knock Out.” Megatron beckoned with one digit.

Knock Out approached the throne Megatron was lounging on. It was very intimidating. A completely inappropriate pulse shot through Knock Out’s array.

“Yes, Lord Megatron.” Knock Out bowed low, hiding his eagerness for the time being. “What service may I provide for you?”

“Kneel before me,” Megatron ordered.

… Not _quite_ their usual, but Knock Out supposed he could indulge Megatron this once. It wasn’t every day he took such a victory over the Autobots.

Knock Out knelt before the throne, level with Megatron’s knees. There was only one thing he could really do from here. Knock Out hid his grimace. Sacrifices were necessary for the greater good, and, in this case, the greater good was overloading on the throne.

Even just the thought of it sent a thrill through Knock Out.

Megatron released his spike, thankfully on its smallest setting. Knock Out pressed forward and slid the tip into his mouth. The metal was hot and alive with a low charge.

This part wasn’t so bad; when the spike’s charge wasn’t crackling and trying to ground itself on any available surface, and before transfluid started getting involved. Knock Out ran his glossa over the smooth metal, hot iron filling his senses.

Megatron's engines revved with pleasure. Knock Out might not be the most practised at this particular form of interface, but he was still damn good at fragging.

Then a servo curled around Knock Out’s helm, pinning him down. He threw himself back, fighting to get free.

There was a terrifying moment when Megatron's servo didn't move and Knock Out thought he was about to shove his spike down Knock Out's unwilling intake, then Megatron let go and Knock Out collapsed backwards, venting desperately.

“Knock Out?” Megatron had something approaching concern in his optics.

“I’m fine,” Knock Out said. He shivered. “I don’t like being held down like that.”

Megatron watched him for a long moment, then leant forward and picked Knock out up and settled him in his lap. Megatron gently spun the wheels on Knock Out’s back.

“You dislike using your mouth,” Megatron said.

“I like being able to talk.”

Megatron laughed. "Unsurprising. Let us find something more suited to both our tastes.”

He rubbed his spike against Knock Out’s aft. That was an invitation Knock Out could get behind.

The throne fit Megatron well, which meant there wasn't much room for Knock Out's legs on either side of his thighs. With a bit of wiggling, Knock Out got his knees in a decent position, but Megatron's sprawl stopped his pedes from fitting too.

It would have to do. Knock Out raised his hips, opened his panel, and slid onto Megatron's spike. _Yes_ , that would do just fine. Except…

“Not that I was complaining earlier,” Knock Out clenched around Megatron’s spike, but it didn’t fill him the way he wanted it to, didn’t give that wonderful _too much_ feeling, “but why not use the entire thing?”

Megatron grunted. “It’s a touch more sensitive this way.”

“You want to overload like this.”

Megatron nodded.

“Alright,” Knock Out said. He tapped a digit against Megatron's chin. “ _But_ I want your whole spike afterwards.”

Megatron pulled Knock Out into a deep kiss, sharp fangs catching his glossa. He decided to take that as a _yes_. Good. He had plenty of tricks to speed his partners along so he could get what he wanted out of an encounter.

Knock Out clenched his valve and started riding.

Megatron rubbed his thumbs along Knock Out’s headlights. Knock Out sent a low pulse of electricity through them, making them glow dimly — no point in blinding a ‘facing partner.

"The Autobots are scattered," Megatron said. "Darkmount has risen. And I have a pretty, shiny mech in my grasp, taking his pleasure. This is my _victory_."

Well, he certainly knew how to make a mech feel appreciated. Knock Out rewarded the praise by digging his clawtips into Megatron’s transformation seams. A pinch of pain always went down well with him — probably a gladiator thing.

“Lord Megatron,” Knock Out said, squeezing Megatron’s spike hard enough to make him rev. “ _My liege_."

He _liked_ that. It gave Knock Out an idea.

Knock Out pressed his arms to his chest, making sure his windows were facing out. It wasn’t quite a truck windshield, but there was a new gleam in Megatron’s optics as he drove up into Knock Out.

Maybe Megatron would like to roleplay sometime. Knock Out could pull off a defeated Prime if he put his processor to it. He'd have to remember to suggest that in a future encounter.

For now, Megatron's charge was getting high and he just needed a little _push_ …

“I yield, _Lord Megatron_.”

Megatron arched and overloaded with a roar, claws gouging gashes into the metal of the throne. Thick, warm transfluid spilt deep within Knock Out's rippling valve. Knock Out shivered from the second-hand charge that somehow managed to reach every contact point, despite Megatron’s spike not stretching him to his limits.

Maybe there was some truth to those rumours of engines mighty enough to power a fusion cannon after all.

"Well done," Knock Out said. "My turn now."

Megatron slid a single extra layer of metal out. Knock Out cycled his valve down desperately.

“I said the whole spike. That’s not nearly enough,” Knock Out complained.

“You’ll get it,” Megatron said, vents finally returning to normal after his overload.

Another layer slid out as Knock Out raised himself up again. Bit by bit, Megatron slid the layers of his spike out until Knock Out was shaking from the pressure and barely able to take it. _Oh_ , it felt so much bigger this way. He should get Megatron to do it like this more often, the build-up was excellent.

“Come on, use me,” Knock Out said. “Do I have to do all the work?”

“I like watching you _exert_ yourself.”

Nonetheless, Megatron curled his long claws around Knock Out's waist and lifted. Squeezing hard enough as he did so that Knock Out could feel his callipers being pressed even tighter around Megatron’s spike.

Megatron bounced Knock Out in his lap and Knock Out’s motor made a shameful squeak of a rev.

Oh, he _liked_ getting big mechs to do what he wanted.

“Gorgeous,” Megatron rumbled. “Perfect. _Mine_.”

And here Knock Out was, in the lap — in the _throne_ — of an emperor, a far sight from the lowly junkyard-caste he’d once been. Autobots could blether about nonsense such as morals and the evils of Decepticons, but Megatron’s crusade had done more for Knock Out than any useless Autobot platitudes.

Knock Out pressed his digits down against his node, wanting to finish before his legs gave out, but Megatron knocked his servo out of the way.

“I was using that!”

Megatron tugged Knock Out closer by his hips and _thrummed_ his engine, giving a perfect vibration that sent Knock Out gasping into overload.

So, so _good_.

Knock Out let his helm drop against Megatron’s clavicle armour. He felt delightfully wrung out.

A quiet _ping_ broke the silence.

“Thank you Soundwave,” Megatron said. Knock Out had forgotten they had a witness. “Shockwave will be making a report shortly. I suggest you make yourself presentable, Knock Out.”

“Me? Unpresentable? Perish the thought,” Knock Out said.

He slid off of Megatron’s lap, snapping his panel closed when all kinds of fluids threatened to leak out. Knock Out took a step and had to grab the arm of the throne for support.

“Oh. That’s.” Knock Out extended his energon prod and leant on it. His legs were taking their sweet time getting the feeling back in them.

Megatron put his spike away and scratched a few red paint transfers off his thighs. If it weren't for the slight tang of ozone in the air — something that could be explained by the open air at this height — there was very little indication that he'd just interfaced.

It was alright for _some_.

At least it was unlikely Shockwave that would care.

* * *

"You should polish."

Megatron looked up from the datapad he was reading — some terribly complex chemical engineering tome of Shockwave's that made Knock Out’s processor ache, he was a dabbler in chemical engineering at best and the theory wasn’t his strong suit — and frowned across the room to where Knock Out was putting the last touches on his own finish. They’d fragged in Megatron's washracks not long ago and now Knock Out was relishing the chance to spend some quality time with his polishes without being interrupted because some idiot Vehicon had put his servo in the engine.

You’d think a few centuries living on the same ship would cure them of that habit.

“You think I need to polish?” Megatron said, tone warming with anger, but he was too satiated to really get furious. “I’m not a flighty Vosian aristocrat, Knock Out.”

“And here I thought ‘flighty’ and ‘Vosian’ meant the same thing. No, you’re the leader of the mighty Decepticon empire.” Knock Out moved closer, a tin of polish in one servo and a cloth in the other. “A certain level of _shine_ is expected from a ruler.”

Megatron scowled and stood, all the better to be intimidating.

… which would’ve worked better on Knock Out if he hadn't just gotten to have all ten and a half metres of Megatron used to make him overload so hard his optics damn near sparked.

“I never needed to _polish_ —” Megatron spat the word, “— in the Pits of Kaon. I started the Decepticons there and I lead as I always have. What use have I of _polish?_ ”

“Some mechs respond better to a leader who takes care of his appearance.”

"He —" Megatron cut himself off with a furious glare. "It was suggested that if I'd bothered to polish — to make a mockery of everything I stood for — before I saw the High Council of Iacon then they would have treated me differently. If I hadn't forced them to see the state the lower castes were in, my address would have been successful."

Oh, this was to do with _Prime_. Knock Out was going to have to tread carefully.

"That's not what I meant," Knock Out said, servos wide in surrender. "I can't speak for anyone from Iacon — not being from there myself — but while I might be more inclined to listen to shinier mechs, all the wax in the universe wouldn't be any help if they were trying to tell me I couldn't be a medic."

“Then why suggest it in the first place?” Megatron grumbled, sounding like a sparkling, but at least that was better than fury.

“I want you to,” Knock Out said. “I want to polish you. Allow me?”

Megatron sized him up, optics still narrowed, but a playful smirk on his mouth now. Then, with a put-upon sigh, he sat back down.

“Do as you will.” Megatron returned his gaze to his datapad. “But no unnecessary fripperies. We are Decepticons, not Autobots.”

"No fancy scents," Knock Out promised. He hadn’t been planning on that anyway, a hint of fruit or an extra sparkle worked for _him_ , but Megatron’s usual aura of warm iron and energon helped his presence.

No, this was purely a visual thing.

Knock Out approached and settled himself in Megatron’s lap, the better to reach his entire torso. He fell into the easy steps of dabbing the cloth in the polish and rubbing firm circles over living metal.

“It’s going to get burnt off the second I reenter the atmosphere,” Megatron complained.

“Then you can reapply it.” Knock Out concentrated on following the sweep of Megatron’s spiked pauldron. “If I had that attitude in the medbay I’d have been terminated by now. ‘Your leg came off? I don’t know why you’re here, you’re going to cease functioning and be disassembled soon anyway, so why waste my time now?’”

Megatron snorted.

The silence that settled was horrifyingly domestic. Knock Out kept polishing Megatron with the occasional mindless comment, and Megatron read his datapad over Knock Out's shoulder.

It wasn’t strictly an intimate thing, shining one another, but it wasn’t something you did with mechs you weren’t at least a little fond of. If Knock Out hadn’t already been sharing Megatron’s berth after interface he wouldn’t have suggested it at all.

However, you had to take comfort where you could and Knock Out enjoyed polishing.

“There,” he said, when he was finally done. "Marvellous."

“Adequate.” Megatron looked himself over. “I suppose this was in part to be able to see your reflection when we’re interfacing.”

“I’m not _that_ narcissistic.” Knock Out snapped the lid of his tin of polish back on. If he was going to do this again he wasn't using his expensive brands. Megatron was _big_ and his scuffs took far more polish than Knock Out had anticipated.

Still, the effect was quite something. Megatron had always been good at drawing optics and now it’d be appreciation keeping them.

After all, what was the point in having a mech that others didn’t want?

* * *

Post _Chain of Command_

“— the Autobots’s pet!” Starscream paced around the lab, ranting. “It doesn’t even understand how the Apex Armour works, but it still put its greasy little appendages all over it and dared to —”

Knock Out hummed in vague agreement whenever he paused for breath. Listening to Starscream had promised to be more interesting than scanning for Predacon energy signatures, but he was starting to repeat himself.

"We should rid the planet of its infestation," Starscream continued. " _Humans_ , pah. If Megatron doesn’t do something about them soon, I’m going to help them choke to death on their own fumes by setting fire to some of their precious fossil fuel sources.”

“Loosen up, Commander,” Knock Out said, throwing in the title to keep Starscream sweet. “Look on the bright side: there was no lasting damage to your frame and we got the Predacon specimen. It wasn’t a total loss.”

“Tell that to Lord Megatron,” Starscream grumbled.

“I’m sure I can tonight,” Knock Out said absentmindedly.

Starscream gaped at him. Had he said something —

Oh, Starscream hadn't known about Knock Out’s _thing_ with Megatron. Likely because they’d settled into somewhat of a routine by the time Starscream had rejoined the _Nemesis_ ; it was old news on the gossip mill.

“Wait,” Starscream said. “No.”

“Yes,” said Knock Out, unable to keep the grin off his face. Not that he wanted to.

“No,” Starscream said again. “Megatron doesn't —”

“Oh, he _does_.”

“Not with _you_ ,” Starscream snapped.

“And what exactly is that supposed to mean?” Knock Out was insulted — he was a highly sought-after mech after all.

“It’s supposed to mean that there’s no way a ground-bound trundler like you would catch Lord Megatron’s optic when far more desirable mechs with _proper_ ornamentation —” Starscream gave his wings a flick, “— have failed to draw his attention in the past.”

“He turned you down,” Knock Out realised.

“Oh, shut up.”

“Don't blame me for your failures, Screamer,” Knock Out said, “Or for our lord's excellent taste. Perhaps if you'd lowered yourself to take a form with wheels you might've gotten somewhere.”

Starscream shuddered.

“Hardly worth it,” he said.

Knock Out let his smug grin speak for itself. Starscream sneered, then his expression suddenly turned sly.

“I suppose someone had to fill in for me, what with my absence,” Starscream said. “And without many options to choose from, poor Megatron must have been desperate to take pity on you and invite you into his berth. I’ll admit you’re better than a Vehicon, though just barely.”

Knock Out narrowed his optics. He was probably lying — he’d basically just admitted to getting turned down — but…

"I'm sure you know there's a reason I've had so many second chances," Starscream continued.

"It certainly can't be because you're any good at your job," Knock Out snapped.

"Why you —! I'm the best Megatron's ever had, you jumped up, four-wheeled _grounder!_ ”

Starscream flounced out of the room. Knock Out tried to focus on the readings Shockwave’s Predacon scanner was churning out, but his processor was too fixated on what Starscream had said.

Had Megatron and Starscream had a thing in the past? It was a running joke amongst Decepticons, but Knock Out had been under the impression it wasn’t true. Megatron had denied it.

 _No_ , Megatron had denied having deep feelings for Starscream, he’d never said they _hadn’t_ interfaced at some point — or at several points — before Knock Out and Megatron had started their… _thing_.

Had Megatron only given into Knock Out’s advances because Starscream hadn’t been around to provide his services?

Knock Out hated how his processor wouldn’t leave well enough alone. _He_ was ‘facing Megatron at the moment and there was no indication that Starscream was too. Megatron hadn’t picked up any new scratches — Knock Out kept an eye on Megatron’s finish, he liked seeing the marks he’d left that Megatron hadn’t bothered to buff out — and Knock Out hadn’t bumped into Starscream loitering around Megatron’s chambers whenever he went to go and have some _quality time_ with their lord and master.

Wings were only attractive if you were into that sort of thing and Megatron hadn’t given any indication that’s where his tastes lay. If anything, his obsession with biting at Knock Out’s tyres was proving the exact opposite.

Starscream was obviously deluded and Knock Out should just focus on his job.

After an extremely dull half an hour, the scanner finally beeped with a positive match. Knock Out looked over the results.

_Oh?_

Knock Out smiled. A faint signal meant the Autobots weren’t likely to be there. A quick retrieval mission and Megatron would be in a good mood and up for a frag.

He’d show Starscream who was worth Megatron’s time.

* * *

Post _Plus One_

Knock Out must have picked up the coil of cabling and put it back down half a dozen times already.

Alright, so Megatron was happy — as happy as their glorious leader ever got these days anyway — and Knock Out was in his good books, but that didn't necessarily mean Megatron was going to be up for something like this.

Frag it. Knock Out grabbed the coil and left his room determinedly. They hadn't tried anything more than a pair of low-power stasis cuffs _once_ — which Megatron had _broken_ halfway through, without Knock Out telling him to — and Knock Out was getting an itch for having someone at his mercy. Surely with his recent success in retrieving a Predacon talon, he'd be allowed to finally have his way.

He nearly wimped out again when he reached Megatron's chambers. He knocked on the door before he could overthink it.

“Ah, Knock Out. Something on your mind?”

Megatron was going over reports and drinking his daily ration. The cube held twice as much as the ones Knock Out got, but then he didn't have jet engines that guzzled fuel like scraplets devoured metal.

Knock Out stepped inside and hit the panel to lock the door — a familiar action by now. He held up the coil of cable.

"You wouldn't happen to have a bit of free time for some fun, my liege?" Knock Out asked.

Megatron put his datapad on a shelf and downed the rest of his cube in one go. Then he closed the distance and took the coil from Knock Out's servo.

"Making good on your threats, Knock Out?"

"Promises," Knock Out said, rising up on the tips of his pedes and tugging Megatron down into a kiss. "It's always been a promise. You'll like it."

He certainly hoped Megatron would. Very little struck Knock Out as more dangerous than a vengeful, _frustrated_ ex-gladiator.

"Haven't I done well recently? Don't I deserve a _reward?_ " Knock Out pushed.

"Just this once," Megatron said.

"Of course. Unless you decide you want more."

Megatron looked sceptical, but allowed Knock Out to take the cable back. Obviously, words weren't going to be useful here, time for action.

"Come here." Knock Out stepped back until his knees hit the edge of the berth. Megatron followed. "Now let me…"

He looped the cable around Megatron's wrist and darted behind him. Megatron halfway followed him, before realising that wasn't the plan.

"Other servo, please."

"I remain unconvinced that this isn't an assassination attempt," Megatron said, even as he tucked his other arm behind his back.

Hmm, the fusion cannon was going to get in the way if Knock Out wasn't careful with his knots.

"There are easier times to attempt assassination," Knock Out said, tightening the coil carefully. "And I at least want an overload first."

Megatron snorted. "It's good to be able to rely on my soldiers always having their own best interests at heart."

Knock Out finished binding Megatron's wrists together. Now for the tricky part.

He threaded the cable around one of the legs of the berth. The entire thing was welded to the wall, but there was a need for structural stability and the leg made a perfect anchor point for his current plans.

Then he pulled on the cable until Megatron could feel the tug on his bound servos.

"What are you scheming, Knock Out?"

"Remember that this is just for interface," Knock Out said, spark in his intake. "I want you to kneel."

There was a deathly silence. Knock Out glanced between the door and the back of Megatron's helm. The cable might hold him long enough for Knock Out to escape.

Then, just as Knock Out was starting to engage his transformation protocols, Megatron dropped to one knee, then the other.

"Good," Knock Out breathed, hoping the fluctuations of his fuel pump weren't as audible to Megatron as they were to him.

He finished tying the cable around the berth leg as quickly as he could and came to stand before Megatron. All that strength and power and he was willing to let Knock Out tie him down. This image alone was worth it, even if Megatron changed his mind and slagged him later.

"Stay high up, if you can," Knock Out said.

Megatron straightened and tugged the bonds experimentally. They held, but with a warning creak that belied how fragile the cable was.

“And what do you expect to get out of this position?” Megatron asked. “You’ll find it hard to take my spike from that angle.”

Oh good, he was playing along. Knock Out loosened his shoulders and flexed his digits in anticipation.

“Then it’s a good thing I’m not after your spike,” Knock Out purred, circling the kneeling warlord, “At least not yet. I wouldn’t want to completely rule it out, of course.”

And here was the tricky bit. Using Megatron’s arms or going off the berth would be easiest to start with, but Knock Out would be the wrong way round when he reached his goal. Thankfully his plating was spaced well enough that Knock Out could probably climb his front without too much difficulty.

“I want you to stay there, upright." Knock Out grabbed Megatron’s pauldron and hoisted himself up. “And I want your mouth on me.”

Megatron laughed. “A feat much more easily achieved with my arms free.”

“Another time.” Knock Out knelt on Megatron’s shoulders, thighs bracketing his helm. Even this high up he was unable to reach the ceiling.

Breakdown's chassis had been much better for balancing on. A nice wide flat box for Knock Out's shins to rest on. And he didn't have to worry about impaling himself if he leant too far right or left.

And not impaling in the fun way either.

The cable creaked again as Megatron’s arms twitched, but he stilled and left them bound. Knock Out eased himself into position and popped his panel.

“You’re here for my pleasure,” he said.

Megatron’s reply was a long, slow lick up Knock Out's valve. _Oh yes_ , that was a clever glossa that was good for much more than just empowering speeches. Hot and wet against Knock Out’s intimate array.

He closed his optics, the better to focus on the sensation of Megatron’s mouth. Someone had taught him how to eat valve and eat it _well_.

Knock Out could get used to this.

"Not so bad, is it?"

Megatron’s fangs grazed the edge of Knock Out’s mesh. Whether in answer or accident, Knock Out couldn’t tell. Either way, it wasn’t _polite_.

“Bite me and I’ll scratch your optics out.”

There was something wrong with Megatron, because the threat just made his engine rev like it did when he did when Knock Out squeezed his spike. The vibrations travelled up and through where Megatron was using his glossa to lap at Knock Out’s mesh.

Not nearly enough, but _promising_.

Let Megatron work that out for himself. Knock Out shifted and had to clutch Megatron’s helm to avoid overbalancing. He should’ve arranged things a bit better and given himself a wall to brace against, however, he’d been too concerned about whether or not Megatron would agree at all to plan that far ahead.

Megatron licked up, tilting his helm further back and attacking Knock Out’s anterior node with short firm strokes. _Oh yes_.

“Good,” Knock Out moaned.

Megatron pressed his glossa flat, covering Knock Out's node and teasing his lips and revved his engine _hard_.

 _Oh_ , almost — _almost!_

Two rough swipes were all it took.

“Oh.” Knock Out overloaded with a jolt, clutching Megatron's helm for balance. “ _Oh!_ ”

Megatron didn't let off with his glossa until Knock Out hissed from overstimulation, then slowed, grounding every last bit of charge until notifications started popping up on Knock Out’s HUD, warning him that he’d have to reroute power from other systems if he wanted to keep his interface array online.

Knock Out could leave it there, he’d overloaded wonderfully and Megatron hadn’t complained yet. He should get down and tend to his berth partner’s overload.

But he had _Megatron_ of all mechs on his knees and — possibly foolishly — decided —

“Another.”

Megatron’s engine growled readily and his glossa returned to work.

* * *

Another overload later, Knock Out’s optics offlined. There was a _snap-snap-snap_ , then he came to, caught by Megatron before he hit the ground. The cable’s frayed ends brushed the floor below.

“Oh, well done,” Knock Out slurred through a thick glossa.

Megatron’s mouth and neck were drenched in Knock Out's pale orange lubricant. It looked like he’d contracted rust. He stretched his jaw, Knock Out could hear the grinding of well-used gears.

“My turn now,” Megatron said, laying Knock Out back on the berth.

Knock Out had to halfway transform his axel to get his tyres out the way enough to lie flat. There was a reason he liked being on top and rarely recharged on his back. Megatron released his spike and slid it straight into Knock Out's soaking valve. There was barely any resistance.

Megatron moved leisurely, almost gently. Like he had all the time in the universe to frag Knock Out into a blissed-out puddle. It was slower than Knock Out’s usual preferences, but it felt pretty damn good after the number his balancing act had done on his back struts.

“Beautiful,” Megatron murmured, “Your joy when I pleasure you is magnificent.”

“And you _like_ pleasing me.” 

Knock Out's processor abruptly decided now was a fantastic time to bring back all his insecurities. He tried to lie back and just enjoy the frag, but it wasn't working.

"You do like pleasing _me_ , don't you?"

"As opposed to whom? All the other mechs currently in my berth?” Megatron licked the tip of Knock Out’s head fin. “I hadn't realised you wanted exclusivity."

Knock Out said nothing. Megatron slowed to a stop and looking down at Knock Out's clenched faceplates.

"What's wrong with you, Knock Out?" Megatron asked, with an expression that might be called worried on someone else. "You were in such a good mood."

"It's nothing," Knock Out said, unsure how much patience Megatron was going to have.

"I prefer my berth partners enthusiastic," Megatron said. "Are you truly concerned that I've been spiking other mechs?"

"It's just… Starscream —"

Megatron cut him off with a derisive snort. "This again? Starscream has a long way to go before he'd be allowed in my berth. Especially when I've got my beautiful little doctor willing to sit on my spike."

That didn't really answer the burning question or deny that Megatron had been fragging other mechs while this _thing_ had been going on. However, as Megatron started slowly thrusting again, he murmured more praise into Knock Out's audial.

And, well, it was difficult to stay insecure when you were being called stunning over and over. Megatron had a knack for sounding sincere during interface.

"Do you want to overload again?" Megatron asked.

Knock Out shrugged. "I'm good." He wasn't sure if he _could_ build the requisite charge for another overload right now.

Megatron kept whispering compliments until he overloaded buried deep in Knock Out, unhurried and satisfying.

Knock Out had never been so glad that he was allowed in Megatron's berth to recharge after their interface sessions. He felt tender, like his paint had been stripped down to the primer, and in dire need of a warm frame to curl up to.

Judging by the kiss Megatron pressed to his helm before settling down to recharge and the gentle — not possessive, like it usually was — servo that curled around Knock Out’s hip, he wasn’t the only one glad of the company.

A successful mission, a full tank, an excellent frag, and a warm berth. Did it get any better than this?

* * *

Post _Thirst_

_Third time's the charm_ , Knock Out thought grimly as he rapped on Megatron's door.

The last time he'd tried to initiate an evening that would leave them both satiated, Megatron had been too busy going over boring minutia with Soundwave. And the time before that, Megatron had turned Knock Out away with a rough grumble about not being in the mood.

If you counted the space Knock Out had given Megatron to get over the insignificant little Terrorcon incident, it had been over a week since they'd interfaced. Over a _week_.

“What do you want, Knock Out?” Megatron said, not even looking at Knock Out when the door slid open.

There was no meddling Soundwave in the room at least, but that wasn't a positive start.

“I was thinking…” Knock Out tried.

“No,” interrupted Megatron tonelessly.

“Why not?” Knock Out snapped. Belated adding, “My liege.”

It had been too long since his last proper overload. He wasn’t about to give up just because Megatron was being contrary.

“Things between us are no more,” Megatron said, dismissing Knock Out with a wave of his servo.

“What? Why?” When Megatron didn’t react, Knock Out stepped closer, clenching his servos. “I deserve an explanation, don't I?”

“I do not wish to have an interface life where actions taken outside the berth affect roles within, yet I find I cannot separate them either,” Megatron said.

Well, that didn't make a lick of sense.

“I thought my punishment was losing my projects,” Knock Out said.

“This isn't about punishment, it's about trust.”

“Trust?”

“Exactly. How can I trust you when you go behind my back with Starscream and destroy half my army?” Megatron snarled.

Well, okay, fair. But still —

“What does that have to do with interface?” Knock Out said.

Trust was important in relationships, absolutely, but this _thing_ was just interface, wasn’t it? And hadn’t Knock Out proved that he wasn’t about to offline Megatron, even when given a perfect opportunity to do so?

“The fact that you have to ask that is concerning in and of itself,” Megatron said. “I will not frag a mech I don’t trust not to intentionally hinder my goals.”

The Terrorcons had been an accident, but Knock Out could tell that pointing that out would be a mistake. It wasn’t fair.

“Your first loyalty has always been to yourself,” Megatron continued, “I accept that. What I cannot accept is that Starscream holds more of your fealty than I do.”

“That’s not true,” Knock Out said.

“No?” Megatron _loomed_. He was scary when he put the effort in; Knock Out quailed. “Time and again you’ve aided Starscream’s plots against me. You _lied_ to my face because Starscream told you to!”

“ _You_ left Breakdown to be dissected by humans!”

Knock Out slapped his servo over his mouth, horrified. That hadn’t been what he’d intended to say.

Megatron laughed humourlessly.

“So, it finally comes out. I suppose giving the order to take out Airachnid puts me responsible for Breakdown’s deactivation too? Or for not dealing with MECH and allowing Cylas to use Breakdown’s frame to become an atrocity?”

“No. I didn’t mean —”

“Surely you must despise me for my role in your mate's disappearance,” Megatron continued.

"I —" Knock Out couldn't finish, couldn't say if that was true or not. Breakdown’s absence was still a hole in his spark, one that Megatron had never been close to filling.

Megatron pointed at the door. “Leave.”

No one could say Knock Out didn’t know a lost cause when he saw it. Such a _shame_.

Knock Out left, servos clenched tight. He hoped there had been an Autobot attack and he’d get to perform some surgery soon. His sawblades itched to carve up a frame.

Unfortunately, only Starscream was loitering around the medbay when Knock Out returned. No doubt ready with another whinge on why Shockwave shouldn’t get any of Megatron’s attention and how he was clearly vying for Starscream’s job — untrue as far as Knock Out could tell, but Starscream had a blind spot as wide as his wings when it came to his coveted second-in-command position.

“Shut up, Starscream,” Knock Out snapped, shouldering past him into the medbay before Starscream even opened his mouth.

“What’s got your paint peeling?” Starscream huffed, following him in. “You've been irritable all week. You weren’t _that_ attached to your synthetic energon project, were you?”

“Oh _please_.” Knock Out rolled his optics. “Maybe I just want five minutes without you screeching at me.”

“Is this because I tried to blame the Terrorcons on you? Because it really was your fault,” Starscream pestered. “And I had to. I’m on my last chance here and you’re kicking thrusters — uh, wheels — with Megatron. Doesn’t that come with _some_ benefits?”

“Shut _up_ , Starscream.”

“Oh.” Knock Out didn’t like the sinister narrowing of Starscream’s optics. “You're not getting any with him anymore.”

“That was your plan all along, wasn’t it?” Knock Out pointed at Starscream accusingly. “You couldn’t bear me succeeding where you failed.”

“You think I wanted the Terrorcons to mess things up that badly?” Starscream snapped. “My wings still ache from _my_ punishment. Being celibate for a while will do you some good, maybe it’ll wipe that smug look off your face.”

"Careful, Screamer, or I'll permanently remove the smug look on _your_ face." Knock Out transformed out a sawblade. "Or, better yet, your _whole_ face."

Starscream sneered. “I liked you better when you knew your place.”

“And where’s that? Where you couldn’t get — beneath Megatron?”

— on top of Megatron — pressed against the wall by Megatron — curled up against Megatron’s shoulder plating —

Starscream’s wings flared up in anger. A warning sign that kept Knock Out from sinking too far into his own processor.

"You're not even a proper combatant!" Starscream snapped. "You're just a medic with ideas above his station, who spends too much time staring in the mirror. No wonder Megatron got tired of you."

Obnoxious Starscream might be, but he had a knack for getting under your plating. It was too much. Any longer here and Knock Out would do something he'd regret.

"Get rusted, Screamer," Knock Out hissed, half wishing the door needed to be opened manually so he could slam it behind him.

He left Starscream in the medbay and stormed off down a random corridor.

Stupid Starscream.

Stupid Megatron.

Stupid Knock Out for being this upset over a convenient frag-buddy.

That’s all it had been. Megatron didn’t actually care for him and Knock Out certainly didn’t care for Megatron beyond a healthy appreciation for how thick his spike was.

It was a _nice_ spike.

Now that was an idea.

 _No_ , Knock Out shook his helm to clear his processor. It was a terrible idea. Megatron would notice if Knock Out removed his spike to use as a ‘face toy the next time he ended up on the slab after a fight with Prime.

Probably.

Some high-grade would be nice about now. It was good for dulling Knock Out’s processor and keeping his more outlandish ideas at bay. Unfortunately, the remains of his stash — mostly untouched since he’d first convinced Megatron to let him take a ride — was in the lab.

The lab where Breakdown’s remains had been left after the Terrorcon incident.

Knock Out hadn’t plucked up the courage to deal with the mess. If it had just been Breakdown’s parts or a single human corpse he wouldn’t have had a problem cleaning up. Part of him had even hoped that Shockwave would want the pieces for his research; though a part closer to his spark knew he’d never give Shockwave the pleasure — Breakdown was his and his alone to avenge.

In the end, the desire for high-grade won over Knock Out’s reluctance and he made his way to the lab.

Knock Out had just pulled out a beautifully fluorescent blue clue from his stash when the smell hit him. He sniffed the cube tentatively, but it only smelled of sweet, sharp fuel. So what was…

Ah, the body.

The fleshy human parts were starting to rot, even with the energon in its systems — regular and dark both — providing a natural preservative. Soon the lab would be uninhabitable from the stench alone.

It was about time that Knock Out dealt with Breakdown’s remains, once and for all. He took a swig of high-grade.

The lab had an incinerator. Normally used for disposing of chemicals and failed experiments — Knock Out supposed that this fell into the latter category — it would have to do in place of a proper smelting pit. There wasn't a chance in the Chaos Bringer’s Pit that Megatron would let Knock Out make a personal trip to Cybertron to find a natural one after the argument they'd just had.

At least there was still enough of an exoskeleton of metal Breakdown pieces that he didn't have to touch the human parts as he ferried it all over and dropped it into the incinerator. The power switch was faulty and it took Knock Out three attempts to light it.

“Well, I’ve fragged things up royally,” Knock Out told the flames, once it had all caught. “You’d laugh at me if you were still here. Of course, if you were still here this wouldn’t have happened. So it’s your fault really.”

The flames hissed as they caught a patch of flesh. Disgusting.

“I know, I know, I should take responsibility for my actions.” Knock Out sighed. “I wish you were still here. I really do. It's been a nightmare keeping myself properly buffed without your help."

If he’d just buffed a bit harder, polished a bit brighter, would that have overcome Megatron’s trust issues? Was he really not desirable enough to be worth any accidents he might cause?

Would he never make it higher than the filthy junkyard-caste he’d started as?

Knock Out gulped some more high-grade.

“I want… I _want_.”

He wanted security. Admiration. _Interface_ and everything that came with it.

He could want until the stars died and he still wouldn’t _get_.

“It figures that I’d finally overreach myself,” Knock Out said. “Did you know I’ve never been dumped before? I’ve always done the dumping. Until you, then I didn’t have to.” He dropped the empty cube onto the floor. He’d clean it up later. Or make a Vehicon do it. “Maybe this is for the best, I’m not sure how long things with Megatron would have gone on for and the last thing I want is to have my finish scratched to pieces because I didn’t let him down gently enough.”

Soon, Knock Out would have to make nice with Starscream, as he was unlikely to find another ally and Starscream could be won over with simple flattery. A few _you're such a good commander_ 's and _Shockwave has no chance of replacing you_ 's and Knock Out would be forgiven.

Unfortunately, such tactics wouldn’t work on Megatron.

It wasn’t _fair_. Knock Out grabbed another cube and drank.

“I _want_ ,” Knock Out whispered, leaning his helm against the incinerator. “I miss you, Breakdown.”

The flames said nothing and Knock Out mourned.

**Author's Note:**

> If anyone's interested I made a visual novel adaptation of Spoon888's MegaStar [Close Quarters](https://archiveofourown.org/works/13963140) fic and Transformatron's MegaStar [Turn A Blind Optic](https://archiveofourown.org/works/16941060) fic. Download page here: <https://transformersvn.tumblr.com/download>


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